The four elements of soil are minerals, water, air and organic matter. Different combinations of the four elements create the four main categories of soil: sand, silt, clay and loam. Of course, we all want loam…but it seldom occurs, especially around homes where topsoil was removed and heavy machines compacted the remaining soil. Most of us have clay.
Growing better soil is actually quite easy…all soils are improved by adding “organic matter” and minerals. Before adding minerals, test the soil to determine its pH (acidity or alkalinity), and any mineral deficiencies. Lime decreases soil acidity, gypsum adds calcium and helps break up heavy clay, and sulfur increases acidity. Other soil amendments to add to a clay soil include sand, cottonseed meal and peat moss.
What is organic matter? Organic matter refers to plant or animal materials decomposed into compost or “humus.” This residue comes from leaves and other plant materials, and certain animal wastes. Uneaten food may be included. The quality depends on the origin of the original biodegradable matter. Many people make their own compost using bins in which materials are mixed until they decompose. Others purchase finished compost.
Humus or organic matter may be added to the garden at any time. Mulching is a simple way to add biodegradable materials to the soil. Evergreen needles, tree leaves, lawn clippings, chicken manure, etc., can be worked into the soil where they decompose. This process improves the air spaces between the soil particles and rearranges the sand, silt and clay to produce optimum soil structure, improving the water retention and drainage balance and making nutrients available to plants.
When soil has proper structure and sufficient nutrients for healthy plants, optimum tilth has been achieved. Congratulations and keep on growing!